1. Technical Field
The present invention relates to a navigation device, a navigation method, and a navigation program, and particularly to a navigation device, a navigation method, and a navigation program for displaying a route object, which indicates a traveling route of a vehicle, so as to be superimposed on a photographed image.
2. Background Art
Conventionally, disclosed is an in-vehicle navigation device in which a photographed image of a view ahead of a vehicle is obtained by image pickup means such as a video camera or the like, and which displays an arrow image, as a route guidance object indicating a traveling direction to which the vehicle is to travel, so as to be superimposed on the photographed image when an vehicle approaches a guidance point such as an intersection or the like (see Patent Document 1, for example).
As described above, the navigation device, which displays the route guidance object so as to be superimposed on the photographed image, is convenient for a user (driver) to compare an actual scene viewed through a windshield with the image on a guide screen. Accordingly, this navigation device provides a driver with intuitive route guidance.
Further, a white line detecting device is disclosed in which a photographed image of a view ahead of a vehicle taken by an in-vehicle camera is inputted, candidate points of a road white line are extracted from the photographed image, a Hough transform on the candidate points of the white line is performed thereafter so as to detect a straight line, and the detected straight line is recognized as a road white line (see Patent Document 2, for example).
Still further, a traffic lane tracking device is disclosed which tracks a traffic lane (lane) ahead of a vehicle by using a detection result of a road white line so as to control traveling of the vehicle (see Patent Document 3, for example).
Still further, a navigation device is disclosed which has guiding means for determining a lane to be traveled along by using the number of traffic lanes and information on a traffic lane along which the vehicle is currently traveling, is the number and the information being obtained from a detection result of a road white line, thereby determining a moving direction and a lane position of the vehicle (see Patent Document 4, for example).    Patent Document 1: Japanese Laid-Open Patent Publication No. 7-63572    Patent Document 2: Japanese Laid-Open Patent Publication No. 63-142478    Patent Document 3: Japanese Laid-Open Patent Publication No. 2005-38225    Patent Document 4: Japanese Laid-Open Patent Publication No. 2004-205527